Specifying RIB® relays for new construction vs. retrofit is often a question of constraints. Where new construction is typically more flexible when it comes to wiring decisions, a retrofit is limited by space and legacy equipment. Functional Devices, Inc. manufactures dry-contact input, wireless, and latching relays—perfect for retrofit projects—as part of our RIB® (Relay-In-a-Box®) line.
What Changes Between New Construction and Retrofit
Three things generally drive relay selection in these cases: the ability (or lack thereof) to run new wiring, knowledge of existing control signals, and whether the space will be occupied while work is ongoing. A retrofit limits all three to varying degrees, so relay selection must be adjusted to compensate.
Specifying RIB® Relays for New Construction
New construction typically allows you to standardize on a few workhorse relays across the whole building rather than specifying a different part for each circuit. An example of this would be the RIBU1C (10 Amp SPDT, universal 10–30 Vac/dc or 120 Vac coil), which accepts most control voltages that a building automation system (BAS) binary output produces. For higher-current switching, the RIB2401B (20 Amp SPDT, 24 Vac/dc or 120 Vac coil) can occupy the same role for larger loads.
Specifying RIB® Relays for a Retrofit
Dry-contact input relays can interface with an existing signal without matching a coil voltage. The RIB01BDC (20 Amp SPDT, Class 2 dry-contact input, 120 Vac power) triggers on a voltage-free contact closure from a legacy panel, switch, or sensor. The input is low-voltage Class 2.
Wireless EnOcean relays remove the need for running control wire entirely. The RIBW24B-EN3 (20 Amp SPDT EnOcean wireless transceiver, 24 Vac power) mounts at the load and pairs with self-powered EnOcean transmitters such as the WWS2-EN3 wall switch and FDLTVC occupancy sensor, with no control wiring needed between them.
Latching relays hold their state on a momentary pulse instead of a continuously energized coil. Functional Devices latching relays (identifiable by their RIBL prefix) retain the last commanded state through a power interruption and draw no continuous coil power, which suits retrofit circuits where holding state and minimizing coil load matter.
Sourcing Relays for Whole-Building Projects
Sourcing the relays, wireless devices, and latching relays for a project from one manufacturer keeps model numbers and documentation consistent. To compare retrofit-compatible models, view our latching and wireless RIB® relays. For project quantities, source parts through local authorized distributors; a distributor can also confirm a substitute model’s rating if a specified part is unavailable.
Frequently Asked Questions About New Construction vs. Retrofit Controls
How does relay selection differ between new construction and retrofit?
When it comes to relay selection, new construction is typically less limited. You can standardize on universal-coil workhorses such as the RIBU1C (10 Amp SPDT) and RIB2401B (20 Amp SPDT). A retrofit often requires dry-contact input relays (RIB01BDC), wireless EnOcean relays (RIBW24B-EN3), and latching relays (the RIBL series) to work around the constraints imposed by legacy signals and finished space.
What relay works when the existing control signal is unknown?
A dry-contact input relay like the RIB01BDC can interface with a legacy panel or sensor output without matching a coil voltage. Its dry-contact input is low-voltage Class 2.
When should a retrofit use wireless relays?
If the space has limitations on running new control wire, a wireless relay can be an effective workaround. An EnOcean relay such as the RIBW24B-EN3 pairs with self-powered EnOcean switches and sensors, with no control wire needed to connect them.
Why use a latching relay in a retrofit?
A latching relay from the Functional Devices RIBL series holds its state on a momentary pulse without a continuously energized coil, and retains that state through a power interruption. This is helpful for retrofit circuits where minimizing coil load or holding state through an outage is important.
Where can I source RIB® relays for a whole-building project?
RIB® relays, wireless devices, and latching relays are sold through authorized Functional Devices distributors. For project quantities, a distributor can confirm stock on the exact model numbers a design calls for, or confirm a substitute model’s rating when a specified part is unavailable.
Ready to Specify for Your Next Project?
To specify RIB® relays for a new-construction or retrofit building automation project, find an authorized Functional Devices distributor near you.